Sulphur cement pre-composition and process for preparing such sulphur cement pre-composition

ABSTRACT

The present invention provides a sulphur cement pre-composition, comprising sulphur and at least an organotitanate, which organotitanate is of the general molecular formula (1): wherein R1 is C n H (2n) —S a R 4  or C m H (2m+1)  and n is an integer in the range of from 1 to 4, m is an integer in the range of from 1 to 30 and a is an integer in the range of from 2 to 8, R4 is S, H, or C p H (2p+1)  and p is an integer in the range of from 1 to 8, XO is an alkoxy or neoalkoxy group, R2 and R3 are, independently, a C n H (2n) —S a R 4 , alkyl, neoalkyl, acyl or aryl group. The invention further provides a process for preparing such sulphur cement pre-composition, processes for the preparation of a sulphur cement product, a sulphur cement product and the use of such sulphur cement pre-composition. The invention even further relates to the use of an organotitanate stabilizing agent.

This application is a 371 filing of PCT/EP08/57277, filed Jun. 11, 2008.

The present application claims priority from European Patent Application07110154.7 filed 13 Jun. 2007

FIELD OF THE INVENTION

The present invention provides a sulphur cement pre-composition and aprocess for the preparation of a sulphur cement pre-composition. Theinvention further provides processes for the preparation of a sulphurcement product, a sulphur cement product and the use of such sulphurcement pre-composition in sulphur cement sulphur mortar or sulphurconcrete.

BACKGROUND OF THE INVENTION

Sulphur cement generally refers to a product comprising at least sulphurand a filler. To improve the properties of the sulphur cement, thesulphur may be modified using a sulphur modifier. Such modifiers areknown in the art.

Usual sulphur cement fillers are particulate inorganic materials.

Sulphur cement-aggregate composites generally refer to a compositecomprising both sulphur cement and aggregate. Examples of sulphurcement-aggregate composites are sulphur mortar, sulphur concrete andsulphur-extended asphalt. Sulphur-extended asphalt is asphalt, i.e.typically aggregate with a binder that contains filler and a residualhydrocarbon fraction, wherein part of the binder has been replaced bysulphur, usually modified sulphur.

It is known to use organosilane compounds as a stabilising agent insulphur cement or sulphur cement-aggregate compositions to improve waterstability. In U.S. Pat. No. 4,164,428 for example, a modified sulphurcomposition (often referred to a plasticized sulphur composition)comprising at least 50% by weight of sulphur, a sulphur modifier (oftenreferred to a sulphur plasticizer), a finely divided particulate mineralsuspending agent, and an organosilane stabilising agent is disclosed. Itis mentioned that suitable organosilanes have the general molecularformula R—Si(OR′)₃, wherein R′ is a low molecular weight alkyl group andR is an organic radical having at least one functional group, usuallybonded to the silicon atom by a short alkyl chain.Gamma-mercaptopropyltrimethoxysilane is mentioned as a preferredorganosilane.

In U.S. Pat. No. 4,376,830 a sulphur cement-aggregate compositioncomprising a sulphur cement and an aggregate containing an expansiveclay and processes for preparing such compositions are disclosed. Theprocesses, and resulting compositions, are characterised by the additionof certain organosilane compounds in the composition prior tosolidifying (cooling) the composition. It is mentioned that suitableorganosilanes have the formula Z—Si(R¹R²R³), wherein R¹, R² and R³ maybe lower alkoxy groups and Z is an organic radical attached to Si via acarbon atom and has at least one molten-sulphur reactive group. Z mayfor example be mercaptoalkyl. Gamma-mercaptopropyltrimethoxysilane ismentioned as a preferred organosilane.Gamma-mercaptopropyltrimethoxysilane is very toxic and has a veryunpleasant smell. There is a need in the art for further stabilizingagents, which improve the water stability of sulphur cement products.

SUMMARY OF THE INVENTION

It has now been found that a stabilizing agent chosen from a group oforganotitanates can be used to prepare sulphur cement products.

Accordingly, the present invention provides a sulphur cementpre-composition, comprising sulphur and at least an organotitanate,which organotitanate is of the general molecular formula:

wherein

R₁ is C_(n)H_((2n))—S_(a)R₄ or C_(m)H_((2m+1)) and n is an integer inthe range of from 1 to 4, m is an integer in the range of from 1 to 30and a is an integer in the range of from 2 to 8, R₄ is S, H, orC_(p)H_((2p+1)) and p is an integer in the range of from 1 to 8,

XO is an alkoxy or neoalkoxy group, and

R₂ and R₃ are, independently, a C_(n)H_((2n))—S_(a)R₄, alkyl, neoalkyl,acyl or aryl group.

The invention in a further aspect provides a sulphur cementpre-composition, comprising sulphur and at least an organotitanate,which organotitanate is of the general molecular formula:

wherein

R₅ is C_(n)H_((2n))—S_(a)—C_(n′)H_((2n′)) and n and n′ each are,independently, an integer in the range of from 1 to 4 and a is aninteger in the range of from 2 to 8,

XO and X′O each are, independently, an alkoxy or neoalkoxy group, and

R₂, R₃, R₆, and R₇ each are, independently, a C_(n)H_((2n))—S_(a)R₄,alkyl, neoalkyl, acyl or aryl group wherein R₄ is S, H, orC_(p)H_((2p+1)) and p is an integer in the range of from 1 to 8.

The invention in a further aspect provides a process for the preparationof a sulphur cement pre-composition according to the invention,comprising admixing sulphur with at least an organotitanate in an amountof at least 0.05 wt % based on the weight of the total composition toobtain a sulphur cement pre-composition, in which process theorganotitanate is of the general molecular formula as definedhereinabove.

The invention in an even further aspect provides a process for thepreparation of a sulphur cement product comprising the following steps:

-   (a) admixing at least sulphur, and organotitanate as defined    hereinabove and a particulate inorganic material at a temperature at    which sulphur is molten to obtain a molten sulphur cement product;    and-   (b) solidifying the molten sulphur cement product.

The invention in a yet further aspect provides a process for thepreparation of sulphur cement product comprising the following steps:

-   (a) admixing at least a particulate inorganic material and    organotitanate as defined hereinabove and allowing the    organotitanate to react with the particulate inorganic material;-   (b) admixing, after step (a), elemental sulphur with the particulate    inorganic material at a temperature at which sulphur is liquid to    obtain an admixture comprising molten sulphur and particulate    inorganic material; and-   (c) solidifying the admixture to obtain a sulphur cement product.

The invention in a still further aspect provides a sulphur cementproduct obtainable by a process for the preparation of a sulphur cementproduct according to the invention.

The invention in another aspect provides the use of an organotitanate asdefined hereinabove as stabilizing agent in sulphur cement, sulphurmortar, sulphur concrete or sulphur-extended asphalt.

The invention in even another aspect provides the use of a sulphurcement pre-composition according to the invention in sulphur cement,sulphur mortar, sulphur concrete or sulphur-extended asphalt.

Reference herein to a sulphur cement pre-composition is to acomposition, which after addition of at least one of sulphur or aparticulate inorganic material forms a sulphur cement product, e.g. asulphur cement, a sulphur mortar, sulphur concrete and sulphur-extendedasphalt.

DETAILED DESCRIPTION OF THE INVENTION

The sulphur cement pre-composition according to the invention comprisessulphur and at least an organotitanate. The organotitanate may be of thegeneral molecular formula:

wherein

R₁ is C_(n)H_((2n))—S_(a)R₄ or C_(m)H_((2m+1)) and n is an integer inthe range of from 1 to 4, m is an integer in the range or form 1 to 30.R₁ is a group, which may provide suitable interaction with the sulphur.Preferably, R₁ is a C_(n)H_((2n))—S_(a)R₄ group. The organotitanate maythen be referred to as a polysulphur-comprising organotitanate. Thesulphur group provides the desired good interaction with sulphur andadditionally it reduces the possible formation of hydrogen sulphide. IfR₁ is a C_(n)H_((2n))—S_(a)R₄ group, a is an integer in the range offrom 2 to 8, preferably of from 2 to 6. R₄ is S, H, or C_(p)H_((2p+1))and p is an integer in the range of from 1 to 8, preferably R₄ is S.

XO is an alkoxy or neoalkoxy group.

Reference herein to a neoalkoxy group is to a group according to formula(3):

wherein:

Z₁, Z₂ and Z₃ are each a monovalent alkyl, alkenyl, alkynyl, aralkyl,aryl or alkaryl group having up to 20 carbon atoms or a halogen or ethersubstituted derivative thereof. In addition, Z₁, Z₂ or Z₃ may also be anoxy derivative of said groups. The various Z₁, Z₂ and Z₃ may eachcontain up to three ether, oxygen or halogen substituents, provided thetotal number of carbon atoms for each such Z group does not exceed 20,inclusive of the carbon atoms contained in substituent portions.

Particularly preferred examples of Z₁, Z₂ and Z₃ groups are alkyl having1 to 8 carbon atoms; aralkyl having 6 to 10 carbon atoms such as benzyl;the aryl and alkaryl groups having from 6 to 10 carbon atoms includingphenyl, naphthyl, tolyl, xylyl; and the halogen-substituted bromophenyl;and the allyloxy-substituted alkyl having from 4 to 20 carbon atoms andthe allyloxy-substituted aryl having from 9 to 20 carbon atoms. Where Z₃is an oxy derivative, the most preferred compounds are the alkoxyderivatives having from 1 to 3 carbon atoms and the phenoxy group.Suitable examples of neoalkoxy groups are (bis2-ethenolatomethyl)propanolato and (bis 2-propenolatomethyl)butanolato.The use of neoalkoxy groups may provide an increased temperaturestability of the stabilizing agent.

Neoalkyl groups are neoalkoxy groups minus the connecting oxygen.

R₂ and R₃ are, independently, a C_(n)H_((2n))—S_(a)R₄, alkyl, neoalkyl,acyl or aryl group. When R₂ and R₃ are alkyl or neoalkyl, R₂O and R₃Oare alkoxy or neoalkoxy groups as defined hereinabove. In that case R₂and R₃ are equal to X.

Preferably, R₂ and R₃ are chosen such that they are, independently,equal to R₁ or X. More preferably, R₂ and R₃ are equal to X as thisprovides the highest number of couplings between the stabilizing agentand the inorganic material.

The organotitanate may also be a polysulphur-comprising organotitanateof the general molecular formula:

wherein:

R₅ is C_(n)H_((2n))—S_(a)—C_(n′)H_((2n′)) and n and n′ each are,independently, an integer in the range of from 1 to 4 and a is aninteger in the range of from 2 to 8, preferably of from 2 to 6.

XO and X′O each are, independently, an alkoxy or neoalkoxy group.Preferably X′O is the same as XO.

R₂, R₃, R₆, and R₇ each are, independently, a C_(n)H_((2n))—S_(a)R₄,alkyl, neoalkyl, acyl or aryl group. R₄ is S, H, or C_(p)H_((2p+1)) andp is an integer in the range of from 1 to 8, preferably R₄ is S. WhenR₂, R₃, R₆, and R₇ are alkyl or neoalkyl, R₂O, R₃O, R₆O, and R₇O arealkoxy or neoalkoxy groups as defined hereinabove. In that case R₂, R₃,R₆, and R₇ are equal to X. Preferably, R₂, R₃, R₆, and R₇ are,independently, equal to X or C_(n)H_((2n))—S_(a)R₄, more preferably R₂,R₃, R₆, and R₇ are equal to X as this provides the highest number ofcouplings between the stabilizing agent and the inorganic material.

Preferably, R₂, R₃, R₆, and R₇ are the same.

Irrespective of the organotitanate used XO and X′O each are,independently, an alkoxy or neoalkoxy group, more preferably a loweralkoxy group, even more preferably an alkoxy group with 1 to 4 carbonatoms, for example methoxy or ethoxy.

Preferably, n has the same value as n′.

Reference is made to U.S. Pat. No. 4,623,738, with respect to thepreparation of organotitanates, especially organotitanates comprisingneoalkoxy groups. Reference is also made to U.S. Pat. No. 4,164,428,with respect to suitable polysulphur-comprising groups.

The sulphur cement pre-composition may comprise the organotitanate inany amount desired. Preferably, the sulphur cement pre-compositioncomprises at least 0.05 wt % of the organotitanate based on the weightof the total composition. More preferably, the sulphur cementpre-composition comprises in the range of from 0.05 to 25 wt %,preferably, 0.5 to 10 wt %, more preferably 1 to 10 wt % of theorganotitanate based on the weight of the total composition. Suchsulphur cement pre-composition may for instance be advantageouslyproduced off-site and used on-site in small volumes. The sulphur cementpre-composition may contain a concentration of organotitanate, which ishigher than the concentration typically used in a process for preparinga sulphur cement product. When used on-site to prepare for instance asulphur cement product, such a sulphur cement pre-composition maysuitably be added in such amounts to an inorganic material that the needfor stabilising agent is satisfied. The sulphur cement product may becompleted by adding additional sulphur and other ingredients if notsufficiently present in the sulphur cement pre-composition. The use ofthe sulphur cement pre-composition removes the need for transporting andon-site storing of organotitanate.

In addition, the sulphur cement pre-composition according to theinvention may comprise a sulphur modifier. Typically, the sulphur cementpre-composition may comprise sulphur modifiers in an amount in the rangeof from 0.1 to 10 wt % based on the weight of sulphur. Such modifiersare known in the art. Examples of such modifiers are aliphatic oraromatic polysulphides or compounds that form polysulphides uponreaction with sulphur. Examples of compounds that form polysulphides arenaphthalene or olefinic compounds such as 5-ethylidene-2-norbornene(ENB) or 5-vinyl-2-norbornene (VNB), dicyclopentadiene, limonene orstyrene.

It will be appreciated that when present the polysulphide group of theorganotitanate and the sulphur may interact. However, such interactionsdo not effect the titanium groups of organotitanate.

The sulphur cement pre-compositions according to the invention may beused in solid or molten state, for instance to prepare a sulphur cementproduct.

The invention also provides a process for preparing a sulphur cementpre-composition according to the invention. In this process sulphur isadmixed with at least the organotitanate in an amount of at least 0.05wt % based on the weight of the total composition, to obtain a sulphurcement pre-composition. The organotitanate may be admixed with thesulphur by any means known in the art. The organotitanate may first bedissolved in a small amount of solvent, for example an alcohol or ahydrocarbon, in order to facilitate the admixing with the sulphur. Thesolvent preferably has a boiling point such that it evaporates duringthe admixing step.

Preferably, the sulphur and organotitanate are admixed at a temperatureat which sulphur is molten. Alternatively, the obtained sulphur cementpre-composition is heated and mixed at a temperature at which thesulphur is molten. The temperature at which sulphur is molten istypically above 120° C., preferably in the range of from 120 to 150° C.,more preferably in the range of from 125 to 140° C.

Mixing at temperatures at which the sulphur is molten may provide ahomogeneous distribution of the organotitanate in the sulphur.

In case the sulphur and organotitanate are admixed at a temperature atwhich sulphur is molten or the obtained sulphur cement pre-compositionis heated and mixed at a temperature at which the sulphur is molten, theobtained sulphur cement pre-composition may be cooled to a temperatureat which the sulphur solidifies. The solid sulphur cementpre-composition can be easily stored or transported.

The organotitanate as defined hereinabove may suitably be used as astabilizing agent in sulphur cement, sulphur mortar, sulphur concrete orsulphur-extended asphalt. In particular, a sulphur cementpre-composition comprising the organotitanate can suitably be used toprepare a sulphur cement product. Reference herein to a sulphur cementproduct is to a sulphur cement or a sulphur cement-aggregate composite.

A sulphur cement typically refers to a composition comprising sulphur ormodified sulphur and a filler. Usual sulphur cement fillers areparticulate inorganic materials with an average particle size in therange of from 0.1 μm to 0.1 mm. The filler content of sulphur cement mayvary widely, but is typically in the range of from 1 to 50 wt %, basedon the total weight of the cement.

Sulphur cement-aggregate composites generally refer to a compositecomprising both sulphur cement and a particulate inorganic materialaggregate. Examples of sulphur cement-aggregate composites are sulphurmortar, sulphur concrete and sulphur-extended asphalt. Mortar comprisesfine aggregate, typically with particles having an average diameterbetween 0.1 and 5 mm, for example sand. Concrete comprises coarseaggregate, typically with particles having an average diameter between 5and 40 mm. Sulphur-extended asphalt is asphalt, i.e. typically aggregatewith a binder that contains filler and a residual hydrocarbon fraction,wherein part of the binder has been replaced by sulphur, usuallymodified sulphur.

In a first process for preparation of sulphur cement product accordingto the invention, a sulphur cement product is prepared by admixing instep (a) at least sulphur, an organotitanate as defined hereinabove anda particulate inorganic material at a temperature at which sulphur ismolten to obtain a molten sulphur cement product. In step (b), after theadmixing step (a), the molten sulphur cement product is allowed tosolidify. Typically, solidification takes place by allowing the moltensulphur cement product to cool down to a temperature below the melttemperature of sulphur.

Preferably, the organotitanate and at least part of the sulphur admixedin step (a) are comprised in a sulphur cement pre-composition accordingto the invention. More preferably, a sulphur cement pre-compositionaccording to the invention comprising a polysulphur-comprisingorganotitanate is admixed, even more preferably a sulphur cementpre-composition comprising a polysulphur-comprising organotitanateaccording to general formula (2). In addition to its function asstabilizing agent, a polysulphur-comprising organotitanate stabilizeraccording to general formula (2) may also provide an additionalmodifying effect. As a consequence less or even no modifier at all needsto be added during the preparation of the sulphur cement product.

Step (a) is carried out at a temperature at which sulphur is molten,i.e. typically above 120° C., preferably in the range of from 120 to150° C., more preferably in the range of from 125 to 140° C. Theconditions under which the particulate inorganic material is admixedwith the organotitanate, preferably comprised in a sulphur cementpre-composition, are preferably such that the organotitanate, preferablycomprised in a sulphur cement pre-composition, is allowed to react withthe inorganic material. The reaction time is typically in the range offrom 20 minutes to 3 hours, preferably of from 30 minutes to 2 hours.

Sulphur, and optionally further ingredients such as sulphur modifiers orparticulate inorganic material, may be admixed with the sulphur cementpre-composition and the particulate inorganic material in step (a).Preferably, all ingredients of the sulphur cement product are admixed ata temperature at which sulphur is liquid.

The organotitanate, preferably comprised in a sulphur cementpre-composition, is admixed with the particulate inorganic material insuch amounts that the molten sulphur cement product comprisesorganotitanate in the range of from 0.01 to 0.2 wt %, preferably of from0.02 to 0.1 wt %, based on the weight of particulate inorganic material.If the organotitanates have reacted during the preparation of thesulphur cement pre-composition, sulphur cement pre-composition isadmixed in such an amount that an equivalent number of titania groupsare present.

In a second process for the preparation of sulphur cement productaccording to the invention, a sulphur cement product is prepared byadmixing in step (a) at least a particulate inorganic material andorganotitanate as defined hereinabove, and allowing the organotitanateto react with the particulate inorganic material. In step (b), after theadmixing step (a), elemental sulphur is admixed with the particulateinorganic material at a temperature at which sulphur is liquid to obtainan admixture comprising molten sulphur and particulate inorganicmaterial. In step (c) the molten sulphur cement product is allowed tosolidify. In this embodiment the organotitanate is not comprised in asulphur cement pre-composition but is admixed with the particulateinorganic material before being admixed with sulphur. The organotitanatereacts with the particulate inorganic material. The reaction time ispreferably in the range of from 20 minutes to 3 hours, more preferablyfrom 30 minutes to 2 hours. The organotitanate may be admixed as suchwith the particulate inorganic material, e.g. by spraying it onto theparticulate inorganic material. Alternatively, the organotitanate may bedissolved in a small amount of solvent, for example an alcohol or ahydrocarbon, in order to facilitate the admixing with the particulateinorganic material. The solvent preferably has a boiling point below thetemperature at which step (a) is performed in order to allow the solventto evaporate during the admixing.

Particulate inorganic materials are admixed with the organotitanate inthe processes according to the invention. In case of a process for thepreparation of sulphur cement, the inorganic material is an inorganicfiller. In the case the process for preparing a sulphur cement productis used for the preparation of a sulphur cement-aggregate composite, theparticulate inorganic material may be filler and aggregate. Theparticulate inorganic material that is admixed with the organotitanatemay be any particulate inorganic material known to be suitable assulphur cement filler or aggregate. Examples of suitable particulateinorganic materials are metal carbonates, e.g. calcium carbonate,asbestos, silica, fly ash, limestone, quartz, iron oxide, alumina,titania, carbon black, gypsum, talc or mica, sand, gravel, rock ormetal-silicates. Such metal silicates are for example formed uponheating heavy metal containing sludge in order to immobilise the metals.More preferably the particulate inorganic material is a calciumcarbonate, silica or a silicate.

In the case that metal-silicates formed by heating sludge for heavymetal immobilisation are used as particulate inorganic material, theheat that is available in the heated sludge can advantageously be usedin the preparation of the sulphur cement product according to theinvention. This can for example be done by using steam that is generatedduring cooling of the metal-silicates for heating the sulphur or theingredients of the process according to the invention.

1. A sulphur cement pre-composition, comprising sulphur and at least anorganotitanate, which organotitanate is of the general molecularformula:

wherein R₁ is C_(n)H_((2n))—S_(a)R₄ or C_(m)H_((2m+1)) and n is aninteger in the range of from 1 to 4, m is an integer in the range offrom 1 to 30 and a is an integer in the range of from 2 to 8, R₄ is S,H, or C_(p)H_((2p+1)) and p is an integer in the range of from 1 to 8,XO is an alkoxy or neoalkoxy group, and R₂ and R₃ are, independently, aC_(n)H_((2n))—S_(a)R₄, alkyl, neoalkyl, acyl or aryl group.
 2. A sulphurcement pre-composition according to claim 1, comprising in the range offrom 0.05 to 25 wt % of organotitanate based on the weight of the totalcomposition.
 3. A process for the preparation of a sulphur cementpre-composition according to claim 2, comprising admixing sulphur withat least an organotitanate in an amount of at least 0.05 wt % based onthe weight of the total composition to obtain a sulphur cementpre-composition, in which process the organotitanate is of the generalmolecular formula:

wherein R₁ is C_(n)H_((2n))—S_(a)R₄ or C_(m)H_((2m+1)) and n is aninteger in the range of from 1 to 4, m is an integer in the range offrom 1 to 30 and a is an integer in the range of from 2 to 8, R₄ is S,H, or C_(p)H_((2p+1)) and p is an integer in the range of from 1 to 8,XO is an alkoxy or neoalkoxy group, and R₂ and R₃ are, independently, aC_(n)H_((2n))—S_(a)R₄, alkyl, neoalkyl, acyl or aryl group.
 4. A processfor the preparation of a sulphur cement pre-composition according toclaim 1, comprising admixing sulphur with at least an organotitanate inan amount of at least 0.05 wt % based on the weight of the totalcomposition to obtain a sulphur cement pre-composition, in which processthe organotitanate is of the general molecular formula:

wherein R₁ is C_(n)H_((2n))—S_(a)R₄ or C_(m)H_((2m+1)) and n is aninteger in the range of from 1 to 4, m is an integer in the range offrom 1 to 30 and a is an integer in the range of from 2 to 8, R₄ is S,H, or C_(p)H_((2p+1)) and p is an integer in the range of from 1 to 8,XO is an alkoxy or neoalkoxy group, and R₂ and R₃ are, independently, aC_(n)H_((2n))—S_(a)R₄, alkyl, neoalkyl, acyl or aryl group.
 5. A processfor the preparation of a sulphur cement product comprising the followingsteps: (a) admixing at least sulphur, and organotitanate as defined inclaim 1 and a particulate inorganic material at a temperature at whichsulphur is molten to obtain a molten sulphur cement product; and (b)solidifying the molten sulphur cement product.
 6. A sulphur cementproduct obtainable by a process according to claim
 5. 7. A process forthe preparation of a sulphur cement product comprising the followingsteps: (a) admixing at least sulphur, and organotitanate as defined inclaim 1 and a particulate inorganic material at a temperature at whichsulphur is molten to obtain a molten sulphur cement product; and (b)solidifying the molten sulphur cement product, wherein theorganotitanate and at least part of the sulphur are admixed in the formof a sulphur cement pre-composition comprising sulfur and theorganotitanate.
 8. A process for the preparation of a sulphur cementproduct comprising the following steps: (a) admixing at least aparticulate inorganic material and organotitanate as defined in claim 1and allowing the organotitanate to react with the particulate inorganicmaterial; (b) admixing, after step (a), elemental sulphur with theparticulate inorganic material at a temperature at which sulphur isliquid to obtain an admixture comprising molten sulphur and particulateinorganic material; and (c) solidifying the admixture to obtain asulphur cement product.
 9. A sulphur cement pre-composition according toclaim 1, comprising in the range of from 0.5 to 10 wt % oforganotitanate based on the weight of the total composition.
 10. Aprocess for the preparation of a sulphur cement pre-compositionaccording to claim 9, comprising admixing sulphur with at least anorganotitanate in an amount of at least 0.05 wt % based on the weight ofthe total composition to obtain a sulphur cement pre-composition, inwhich process the organotitanate is of the general molecular formula:

wherein R₁ is C_(n)H_((2n))—S_(a)R₄ or C_(m)H_((2m+1)) and n is aninteger in the range of from 1 to 4, m is an integer in the range offrom 1 to 30 and a is an integer in the range of from 2 to 8, R₄ is S,H, or C_(p)H_((2p+1)) and p is an integer in the range of from 1 to 8,XO is an alkoxy or neoalkoxy group, and R₂ and R₃ are, independently, aC_(n)H_((2n))—S_(a)R₄, alkyl, neoalkyl, acyl or aryl group.
 11. Asulphur cement pre-composition according to claim 1, comprising in therange of from 1 to 10 wt % of organotitanate based on the weight of thetotal composition.
 12. A sulphur cement pre-composition, comprisingsulphur and at least an organotitanate, which organotitanate is of thegeneral molecular formula:

wherein R₅ is C_(n)H_((2n))—S_(a)—C_(n′)H_((2n′)) and n and n′ each are,independently, an integer in the range of from 1 to 4 and a is aninteger in the range of from 2 to 8, XO and X′O each are, independently,an alkoxy or neoalkoxy group, and R₂, R₃, R₆, and R₇ each are,independently, a C_(n)H_((2n)-)S_(a)R₄, alkyl, neoalkyl, acyl or arylgroup wherein R₄ is S, H, or C_(p)H_((2p+1)) and p is an integer in therange of from 1 to
 8. 13. A sulphur cement pre-composition according toclaim 12, comprising in the range of from 0.05 to 25 wt % oforganotitanate based on the weight of the total composition.
 14. Aprocess for the preparation of a sulphur cement pre-compositionaccording to claim 13, comprising admixing sulphur with at least anorganotitanate in an amount of at least 0.05 wt % based on the weight ofthe total composition to obtain a sulphur cement pre-composition, inwhich process the organotitanate is of the general molecular formula:

wherein R₅ is C_(n)H_((2n))—S_(a)—C_(n′)H_((2n′)) and n and n′ each are,independently, an integer in the range of from 1 to 4 and a is aninteger in the range of from 2 to 8, XO and X′O each are, independently,an alkoxy or neoalkoxy group, and R₂, R₃, R₆, and R₇ each are,independently, a C_(n)H_((2n)-)S_(a)R₄, alkyl, neoalkyl, acyl or arylgroup wherein R₄ is S, H, or C_(p)H_((2p+1)) and p is an integer in therange of from 1 to
 8. 15. A sulphur cement pre-composition according toclaim 12, comprising in the range of from 0.5 to 10 wt % oforganotitanate based on the weight of the total composition.
 16. Aprocess for the preparation of a sulphur cement pre-compositionaccording to claim 15, comprising admixing sulphur with at least anorganotitanate in an amount of at least 0.05 wt % based on the weight ofthe total composition to obtain a sulphur cement pre-composition, inwhich process the organotitanate is of the general molecular formula:

wherein R₅ is C_(n)H_((2n))—S_(a)—C_(n′)H_((2n′)) and n and n′ each are,independently, an integer in the range of from 1 to 4 and a is aninteger in the range of from 2 to 8, XO and X′O each are, independently,an alkoxy or neoalkoxy group, and R₂, R₃, R₆, and R₇ each are,independently, a C_(n)H_((2n)-)S_(a)R₄, alkyl, neoalkyl, acyl or arylgroup wherein R₄ is S, H, or C_(p)H_((2p+1)) and p is an integer in therange of from 1 to
 8. 17. A sulphur cement pre-composition according toclaim 12, comprising in the range of from 1 to 10 wt % of organotitanatebased on the weight of the total composition.
 18. A process for thepreparation of a sulphur cement pre-composition according to claim 12,comprising admixing sulphur with at least an organotitanate in an amountof at least 0.05 wt % based on the weight of the total composition toobtain a sulphur cement pre-composition, in which process theorganotitanate is of the general molecular formula:

wherein R₅ is C_(n)H_((2n))—S_(a)—C_(n′)H_((2n′)) and n and n′ each are,independently, an integer in the range of from 1 to 4 and a is aninteger in the range of from 2 to 8, XO and X′O each are, independently,an alkoxy or neoalkoxy group, and R₂, R₃, R₆, and R₇ each are,independently, a C_(n)H_((2n)-)S_(a)R₄, alkyl, neoalkyl, acyl or arylgroup wherein R₄ is S, H, or C_(p)H_((2p+1)) and p is an integer in therange of from 1 to 8.